Archive for February, 2008

Vitamin Profile – Vitamin B6 (Pyridoxine)

Interactions

Pyridoxine can interact with barbiturates, levodopa (1 – dopa, given for Parkinson’s disease), phenytoin (for seizures), isoniazid and cycloserine (used to treat tuberculosis), hydralazine (for hypertension), penicillanime (a treatment for arthritis and Wilson’s disease), oral contraceptives, and vitamin B12.

Therapeutic Uses

Pyridoxine supplements may be given to counteract any of the symptoms of vitamin B6 deficiency. However, such symptoms will not be alleviated by pyridoxine unless they are, in fact, caused by Vitamin deficiency.

In addition, pyridoxine has been found to have some therapeutic value for the following conditions.

Depression Associated with Oral Contraceptives

There is limited evidence suggesting that supplemental B6 may be of some value in partially reversing the depression occasionally associated with the use of oral contraceptives. The reason for this is that the estrogenic component of the pill alters blood levels of pyridoxine and therefore increases the daily requirement. Pyridoxine is needed to form brain neurotransmitters, and it also binds weakly to steroid hormone receptors.

Large-scale controlled trials are lacking to confirm this observation. However, we recommend B6 supplementation in doses of 25 to 100 mg per day for those women taking oral contraceptives who have experienced troublesome depression and not achieved relief from another therapy. Since this depression is specifically caused by B6 deficiency, vitamin B6 therapy should not be viewed as of general value in the treatment of any other form of depression.

Premenstrual Syndrome

Vitamin B6 has also received publicity as a treatment for this common problem. The theory here is that the symptoms of premenstrual syndrome (PMS) are caused by a hormone imbalance associated with menstruation. Advocates of this therapy say that the situation is similar to oral contraceptive-related depression and the marginal deficiencies reported among pregnant women. Another possible mechanism of action may be the ability of high doses of B6 to bind to steroid hormone receptors. In any event, there have been at least five small, randomized, placebo-controlled trials addressing the question of the usefulness of B6 to relieve PMS. We can summarize the evidence by simply indicating that the results are not in agreement. Most studies show a small improvement with B6 compared to placebo, and some women claim significant relief from PMS with B6.

Our advice: B6 may be worth a try if PMS is a problem. A dose of 100 to 200 mg per day (100 mg twice a day) should be used, but do not take over 200 mg per day due to toxicity risks. Take the B6 only during the two weeks prior to menses, that is, during the time when PMS occurs. If after a test of one or two cycles it does not seem to be helpful, stop its use. B6 seems to work only for some women, not all, and one cannot predict who will benefit and who will not.

Reduction of Breast Milk

Some European physicians have employed daily doses of 50 mg of pyridoxine to purposely suppress prolactin secretion and reduce milk re¬production in women who have just given birth. High-dose pyridoxine has been hailed as a savior because it may replace the hormones that have been used for this purpose. There is not much information to support this use of B6.

Treating Inborn Errors of Metabolism

There are at least six rare, inherited genetic defects that can be treated by giving high doses of vitamin B6. Studies have shown that in most cases these defects are the result of a genetic error that leads to the manufacture of a defective enzyme. The defect is usually related to the enzyme’s inability to bind tightly to its needed vitamin. If the enzyme cannot bind to the vitamin, it can not function. Extraordinarily high vitamin doses may be able to “flood” the enzyme, so even though the vitamin is not tightly bound to the enzyme, it can still work.

These are not true vitamin-deficiency diseases. They are defects in a single enzyme that can be overcome by megadoses of the appropriate vitamin. The abnormally low enzyme activity can lead to a variety of symptoms, but usually the problem is revealed during early childhood in the form of mental retardation and failure to grow and thrive.

There are several examples of B6-dependent inborn errors of metabolism. These rare but serious defects often respond seemingly miraculously to vitamin treatment. It must be emphasized that most cases of mental retardation or developmental problems will not respond to vitamin treatments. Only a specialist can pinpoint cases that will respond and the exact vitamin needed.

Carpal Tunnel Syndrome

The sheath of tissue that carries the tendons and the median nerve through the wrist to the hand is called the carpal tunnel, and for unknown reasons, the size of the opening can become reduced. When this happens, the nerves passing through become compressed, with resulting pain, loss of touch sensation, loss of strength, and tingling sensations in the hand. Carpal tunnel syndrome can accompany several disease states, but more commonly it appears as a result of repetitive motions of the hand and wrist. It is frequently seen in data entry personnel, carpenters, joiners, violinists, and writers, for example. Pain at night interferes with sleep, and loss of strength in the hand sometimes makes work impossible. The only sure treatment is surgery to open up the tunnel and to relieve pressure.

One well-known research group in Texas has published numerous reports on the successful use of vitamin B6 to relieve carpal tunnel syndrome. They believe that carpal tunnel syndrome is related to vitamin B6 deficiency. However, the published experiences of other investigators have not been so enthusiastic about the value of B6 treatment. More recent clinical trials have indicated that B6 therapy relieves pain to some extent but may not improve nerve conduction function. This implies that the B6 is affecting pain thresholds and may not be doing much to improve the underlying reason for the pain. Thus inflammation and damage may be continuing, but you don’t feel the pain as much.

B6 therapy should be undertaken only with the guidance of a health care professional experienced in dealing with carpal tunnel syndrome. Doses of B6 should be 100 to 300 mg per day and continue for at least three months. This is about two hundred times the RD A value. If signs of toxicity develop (numbness in the legs, for example), discontinue use immediately.

Relieving Morning Sickness

Pyridoxine has been combined with an antihistamine and promoted for the treatment of morning sickness. This combination was called Benedectin and was sold in the United States for almost two decades until it was withdrawn in 1982. The withdrawal was a voluntary action on the part of the manufacturer because the question was raised of this product’s potential for causing birth defects. High doses of pyridoxine have caused birth defects in laboratory animals, and while this lab data can not be directly translated to human beings, Bendectin was with-drawn because of the manufacturer’s desire to avoid adverse publicity and the staggering cost of potential lawsuits. Thus, the issue was never resolved to anyone’s satisfaction. There is evidence to support the role of pyridoxine in the treatment of morning sickness. But we recommend mat pregnant or breast-feeding women take pyridoxine only for nutritional purposes, unless it is taken under medical guidance.

In addition, there is nothing to indicate this vitamin is valuable in treating nausea and vomiting caused by conditions other than pregnancy.
Water-Soluble Vitamins: Vitamin B,,

Cardiovascular Disease

In recent years, elevated blood levels of an amino acid called homocysteine have been associated with a higher risk of heart disease and blood vessel disease (atherosclerosis). Pyridoxine is one of three vitamins (the others are B12 and folic acid) that are involved in getting rid of homocysteine in the body. RDA levels of vitamin supplements will usually normalize homocysteine levels. Our message is simple: Take a multivitamin/mineral supplements that contains 100 percent of the RDA for B6, B12, and folic acid. Unless you have a rare inborn error of metabolism, this will keep homocysteine levels at an appropriate value.

UNSUBSTANTIATED CLAIMS

We cannot recommend that you take vitamin B6 to treat arthritis, diabetes, mental retardation, numbness, or obesity. B6 will also not prevent aging, fluid retention, or leg cramps, nor can it improve — your vision or help you lose weight.

Vitamin B6 has been used to treat a variety of mental disorders, including childhood learning disabilities, autism, schizophrenia, and Alzheimer’s disease. The evidence for value of B6 here is conflicting and inconclusive. Low levels of B6 have not been found in mental disease patients.

AVAILABILITY

Vitamin B6, as pyridoxine hydrochloride tablets, can be purchased without a prescription in strengths between 25 and 100mg. Several timed-release preparations are also available, but the value of timed-release vitamins is questionable. Pyridoxine hydrochloride (100 mg) injection is available only on a doctor’s prescription.

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Vitamin B6 (Pyridoxine)

Vitamin B6 actually consists of six substances: pyridoxine, pyridoxine phosphate, pyridoxal, pyridoxal phosphate, pyridoxamine, and pyridoxamine phosphate. All have the same potency. Pyridoxine is considered synonymous with vitamin B6, but technically vitamin B6 is a better descriptive term because it encompasses all active forms of the vitamin. Although a great deal is known about the processes in which B6 is involved in the body, there are still many unanswered questions about its importance and function in humans. With the discovery that B6 is involved in eliminating homocysteine, more attention is being given to this vitamin because of possible implications in heart disease prevention. High blood levels of homocysteine are now considered a risk factor for atherosclerosis, blood vessel disease, and deep vein clot formation, all of which are key factors in the development of angina pains, heart attacks, strokes, transient ischemic attacks (TIAs, or mini-strokes), and disease of leg arteries.

FUNCTION

Pyridoxal phosphate is the active form of vitamin B6 in humans and is manufactured by our bodies from pyridoxine or from the other forms of the vitamin. People who are magnesium-deficient may be less able to make the active form of this vitamin, as magnesium plays an essential role in phosphate transfer reactions. Also, riboflavin is involved in the conversion of B6 into the active form of the vitamin; riboflavin deficiency (itself rare) can lead to a B6 deficiency.

Pyridoxal phosphate is required by at least a hundred differ¬ent enzymes, including those involved in the formation and reactions of amino acids used as building blocks for protein. Pyridoxal phosphate is also needed for proper brain and central nervous system function, because many chemical transmitters, used by the brain for communication, depend on B6 as a coenzyme (catalyst) in their formation from simple amino acids. B6 deficiency can affect mental health and lead to convulsions.

Other important functions of this vitamin include catalyzing the manufacture of hemoglobin (responsible for carrying oxygen from the lungs to every cell in the body) and conversion of the chemical tryptophan to niacin. The latter is essential to normal body operation, because about half of our niacin comes from tryptophan converted by the body.

DAILY REQUIREMENTS

Daily pyridoxine requirements vary with the amount of protein in the diet The more protein you eat, the greater your need for pyridoxine. The recommendation is 1.5 mg for every 100 g of dietary protein. The adult RDA value is 2 mg for males and 1.6 mg for females.

DIETARY SOURCES

B6 is found as pyridoxine in vegetables; in animals and; products, B6 activity is supplied by pyridoxal or pyridoxamine. As indicated above, the various forms are identical in terms of vitamin B6 activity. The vitamin is present in a variety of foods, and rich sources include meats, grains, fish, eggs, and carrots. Additional good sources are listed in the accompanying table.

There is no evidence to support the contention that B6 deficiency is widespread in the United States. It can be found in many foods, and some usable B6 is made by bacteria in the gastrointestinal tract.

Vitamin B6 content of Selected Foods
(Average adult RDA is 2 mg)

FOOD APPROXIMATE CONTENT (MG PER 3OZ)

Avocadoes 0.44
Bananas 0.31
Beef 0.26
Bran 0.90
Brewer’s yeast 3.40
Carrots 0.17
Cashew nuts 0.36
Eggs 0.43
Fish 0.43
Hazelnuts 0.59
Lentils 0.41
Liver (calf’s) 0.60
Peanuts 0.36
Pork 0.28
Potatoes 0.39
Rice (white) 0.76
Salmon 0.88
Soybeans 0.62
Shrimp 0.54
Sunflower seeds 0.98
Tuna 0.32
Turkey 0.36
Wheat bran 0.90
Whole wheat flour 0.51

Routine B6 supplementation is probably not necessary as long as your diet is reasonable. Nevertheless, it is included in virtually every available multivitamin product. An exception may be made for the elderly, since marginal B6 deficiencies have been noted in the elderly, especially elderly hospitalized patients. We recommend that all people over age sixty-five take a complete multivitamin/mineral supplement.

Pyridoxine is relatively stable in foods during processing, although as much as 25 percent of the vitamin activity may be lost during cooking. It is also quite stable when food is frozen dehydrated, but it is destroyed by ultraviolet light, and so B6 containing foods should be stored in dark or opaque containers. Other forms of the vitamin—pyridoxal, for example, found in meat—are even less stable when heated. The milling and refining of whole wheat destroys most of its pyridoxine content, which is not replaced in the enriched flour used by most consumers. Thus while the amount of B6 in one’s diet is highly variable, nevertheless it is usually adequate for prevention of deficiency symptoms.

DEFICIENCIES

Since pyridoxine is involved with brain function, the of hemoglobin in red blood cells, and the manufacture of body proteins, B6 deficiency is reflected in the impairment of all these biological functions. While severe pyridoxine deficiency is rarely seen because of the widespread presence of B6 in the diet, mrginal deficiencies may be found in some special circumstances including people taking several drugs that interact with pyridoxine. Therapy with the antituberculosis drug isoniazid is the best-documented case where signs of B6 deficiency may be observed. Obvious deficiency states have also been produced under test situations by feeding volunteers 4-deoxypyridoxine which counteracts vitamin B6.

Deficiency Symptoms

Under test conditions, nervous system abnormalities such irritability, confusion, nervousness, and numbness in the hands and feet were observed. Skin lesions similar to those seen with niacin (B6 is needed for the body to synthesize niacin) and a magenta coloration of the tongue have also resulted after several weeks of a pyridoxine-deficient diet plus the vitamin antagonist 4-deoxypyridoxine. Convulsive seizures can develop if the vitamin is withheld for extended periods. Some time ago an incident occurred in which three hundred infants were mistakenly given pyridoxine-deficient baby formula. These children became nervous, and several of them experienced convulsions before the problem was discovered and corrected. Severe B6 deficiency I cause anemia in humans, but this rarely occurs in people who are simply deficient in dietary B6 intake. This anemia can easily reversed by taking vitamin B6. B6-deficient patients also feel tired and listless.

It is possible to determine vitamin B6 deficiency by giving a person a loading dose (a large dose all at once) of the chemical by mouth. The patient will then pass a number of unusual metabolites of tryptophan out of his or her body via the urine. One of these, xanthurenic acid, is a convenient measure of B6 deficiency. This test, however, is not routinely used. A blood test for the activity of a specific pyridoxal phosphate-dependent is a more convenient screening method.

People Who May Benefit From Supplementation

Pregnant women need extra pyridoxine for several reasons. The growing fetus requires a considerable amount of energy, extra vitamins , and other nutrients from the mother. Also, estrogenic present in larger-than-usual amounts during pregnancy, tend to change amino acid metabolism and increase the need for pyridoxine. Since abnormally low pyridoxine levels have been reported during pregnancy, expectant mothers should take a special prenatal vitamin formulation that provides about 2.5 mg of pyridoxine per tablet.

Toxicity

B6 is considered nontoxic in daily doses up to between 20 and 50 mg. However, there have been a small number of incidents of sever nerve disorders after taking vitamin B6 megadoses. The doses taken were as high as 6 g (6,000 mg) per day, or three thousand times the average adult RDA. These people had difficulty walking, their hands became numb and difficult to control, they lost some sensory perception (touch, temperature, vibration, pinprick, and feeling of position), and they lost feeling in the area around their mourn. All improved after they stopped taking the vitamin, but the recovery took as long as seven months in some cases, and some symptoms remained even at that time. Since then, these symptoms have been noted in people taking as little as 50 mg a day of the vitamin, although adverse effects at doses below 500 mg per day are very rare.

Animal studies have shown doses equivalent to between 200 and 600 mg per day in humans will decrease blood levels of prolactin, a hormone involved in breast milk production. Some people have suggested that B6 be avoided by nursing mothers, but there is no evidence that the amounts of pyridoxine contained in normal vitamin supplements can affect breast milk production.

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Vitamin B5 (Pantothenic Acid)

The name of this vitamin (derived from the Greek word pan, meaning “all”) means “from everywhere”. Pantothenic acid does indeed live up to its name; it is found throughout our environment. As a result, this vitamin is unique in that severe human deficiencies have almost never occurred naturally. Symptoms of deficiency have been produced only under extreme or experimental conditions.

Function

Pantothenic acid is converted in the human body to a cofactor called coenzyme A. coenzyme A is a high-energy compound used in the transfer of a variety of substances during normal body processes. These include the metabolism of carbohydrates, the breakdown and synthesis of fatty acids, the generation of glucose from glycogen (the form in which glucose is stored in the liver), and the body processes that make such substances as steroid hormones. Intermediates in the metabolic cycles that convert glucose (from the digestion of carbohydrates) to carbon dioxide and water and energy all have coenzyme A attached to them. Thus, if it were possible to remove all pantothenic acid from our bodies, we would die because we couldn’t process food into energy and into the materials our bodies use to build tissues.

Daily Requirements

There are no established standards for pantothenic acid, and it is therefore not included in the RDA tables. However, the Food and Nutrition Board of the National Academy of Sciences has established 4 to 7 mg as a safe and adequate daily adult intake. These standards are only an estimate of daily requirements and can not be taken as precise needs.

Dietary Sources

Most Western diets contain more than enough pantothenic acid. Some of the richest sources are meats (especially organ meats), corn, lentils, eggs, nuts, and lobster. Additional good sources are listed on the accompanying table.

Cooking losses of up to 30 percent occur during prolonged heating of acidic foods. Also, much of the pantothenic acid content of whole wheat flour is lost during processing to white flour.

Pantothenic Acid Content of Selected Foods
(Average adult safe and adequate daily intake is 5.5 mg)

FOOD APPROXIMATE CONTENT (MG PER 3 OZ)

Almonds 0.43
Apricot nectar 0.86
Avocadoes 0.94
Beans 0.34
Blue cheese 1.53
Brewer’s yeast 9.35
Broccoli 1.20
Cashew nuts 1.11
Cheese 0.43
Chicken 0.77
Chickpeas 1.02
Corn 4.25
Eggs 1.96
Egg yolk 3.57
Lamb 0.50
Lentils 1.40
Lobster 1.28
Milk 0.34
Mushrooms 0.85
Peanuts 2.38
Peas 2.90
Pomegranate 0.54
Potatoes 0.50
Salmon 0.68
Sardines 0.77
Soybeans 4.42
Sunflower seeds 4.25
Tuna 0.43
Turkey 0.77
Walnuts 0.77
Wheat germ 1.87

Deficiencies

Volunteers fed a pantothenic acid – free diet under experimental conditions took ten weeks to develop deficiency symptoms. Others fed a similar diet and given a substance that counteracts the effects of pantothenic acid developed the symptoms in a shorter period of time.

Deficiency Symptoms

Deficiency symptoms consisted of nausea, numbness in the extremities, sleep disturbances, muscle spasms and cramps, poor muscle coordination, headache, fatigue, stomach pains, stomach gas and diarrhea, and occasional vomiting. Subsequent studies have shown that people deprived of pantothenic acid had fewer antibodies in their blood and were not as well protected against foreign substances such as bacteria.

During World War II, prisoners of war complained of “burning feet” syndrome, associated with tingling and numbness in the legs. These symptoms can occur in anyone who is malnourished and may represent a form of pantothenic acid deficiency, since they respond to vitamin treatment. However, a direct relationship has not been established.

The relationship between symptoms of pantothenic acid deficiency and its function is not always as apparent as that relationship is in other vitamins. However, pantothenic acid deficiency can lead to nerve and muscle disorders because of its role in fat and glucose metabolism; decreased immune response because of decline in steroid metabolism; and gastrointestinal problems because of a decline in normal cell function in the gastrointestinal tract.

Toxicity

Pantothenic acid is nontoxic. People have taken doses as high as 10 g (10,000 mg) a day with no known adverse effects.

THERAPEUTIC USES

Pantothenic acid supplements may be given to counteract the symptoms of pantothenic acid deficiency reviewed earlier this profile. However, such symptoms will not be alleviated by pantothenic acid unless they are, in fact, caused by vitamin deficiency.

Pantothenic acid is also sold as dexpanthenol (D-pantothenyl alcohol), a lotion or cream to be applied to burns, cuts, or abrasions. This product relieves itching and is soothing to wound. Experiments have shown that dexpanthenol can help speed up the healing process following minor surgery to nasal sinuses. Topical use of pantothenic acid seems worthwhile for minor wounds and inflammation.

UNSUBSTANTIATED CLAIMS
Alleviation of Stress

Pantothedc acid has been promoted as an “antistress” vitamin. The origins of this alleged property lie in animal studies and the human experiments described under “Deficiencies” above. Advocates for this use of pantothenic acid feel that it will prevent stress and stress-related diseases because people in whom a vitamin deficiency was created were less able to respond to stressful situations. There is, however, no factual evidence that pantothenic acid will prevent or treat any other forms of stress.

Weight Reduction and Acne Treatment

Pantothenic acid has been promoted for use in weight loss programs. The rationale for this claim is that this vitamin facilitates a complete breakdown of fats, thus decreasing the amount stored. Proponents claim that hunger is reduced and stored fat is better metabolized during dieting. Large doses of pantothenic acid (over 1 g) are used. The same rationale is advocated for the application of pantothenic acid for acne treatment. Here, a more complete breakdown of fatty acids is proposed to decreasing the plugging of pores that starts the acne lesion. While these hypotheses are interesting, controlled studies are lacking to demonstrate benefits.

Other Uses

We cannot recommend that you take this vitamin to treat alcoholism, allergies, arthritis, constipation, fatigue, liver cirrhosis, shock, or stomach ulcers.

Availability

Pantothenic acid is available without a prescription as calcium pantothenate. It comes in strengths from 25 mg to 500 mg. the alcohol derivative (dexpantothenol) is also marketed as lotion or cream.

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There are a lot of ways of losing weight, everybody knows that.we are bombed by hundreds and hundreds of products and programs and all.We will give some advice and plans about it, but we shall begin with some clearings over a few factors that might take you back from your weight loss plan:

People say that a fancy exercise machine burns more fat than regular exercises.WRONG! - caloric expenditure is directly related to the amount of effort an activity requires. In general, the more difficult it feels, the more calories you burn. The easier it feels the fewer calories you burn.

People say that:Weight training with free weights is much more effective than with machines.WRONG. For the purposes of general fitness, muscle toning, and weight loss, it doesn’t matter.

People say that: Exercising for 30 minutes two to three times per week is sufficient for weight loss.WRONG.It is not bad, of course, because you are doing something which is surely better then nothing but I recommend working up to 30 to 60 minutes of daily aerobic exercise and three days of weight training per week.

People say that you can’t lose weight.WRONG. Of course you can, it simply happens slower but this is the way we have been designed.

People say that working out on an empty stomach helps you lose more weight.WRONG, of course. This could only prevent you from having enough energy when you do sports or faint.It doesn’t affect your weight.try to at least drink a fresh before you start working out.

The idea is: Lose Weight ,it’s not that difficult.

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Vitamin B3, Niacin, is the word most often used to describe chemical compounds having vitamin B3 activity. Nicotinic acid (niacin) and nicotinic acid amide (nicotinamide) are both found in vitamin preparations. They are of equal nutritional potency. In the body, the forms of the vitamin that participate in biochemical re¬actions (called coenzymes) are nicotinamide adenine dinucleotide (NAD) and nicotinamide adenine dinucleotide phosphate (NADP). Nicotinic acid can be easily converted to nicotinamide and to NAD and NADP in the body. On the surface, niacin ap¬pears to be similar in function to thiamin (vitamin B1), but the two vitamins are actually involved in energy metabolism in somewhat different ways.

Niacin deficiency is called pellagra. Epidemics of pellagra occurred in southern Europe in the mid-eighteenth century and in the Midwestern and southern United States in the early 1900s. the corn-based diet then prevalent in those areas led to this debilitating and sometimes fatal deficiency disease. Corn is low in tryptophan, an amino acid that can be converted to niacin, a and the niacin contained in corn is not easily assimilated by our bodies. Pellagra has virtually disappeared in the United States since white flour began to be enriched with niacin in 1939.

Nicotinic acid is not related to nicotine, as the name might imply.

Function

Niacin must be converted to NAD or NADP before it can affect your body. Both NAD and NADP are coenzymes (catalysts) for more than 150 different cellular reactions involved in generating energy for normal cell function. NADP is also important for many body reactions that manufacture necessary fatty acids and in the metabolism and elimination of drugs and chemicals from the body.

Daily Requirements

Daily niacin requirements depend on the number of calories you eat and the amount of energy you expend each day. At least 4.4 mg of niacin is required for every 1,000 calories of energy expended to prevent pellagra, but the RDA is set at 6.6 mg for every 1000 calories. Your daily intake should never fall below 13 mg. People who expend large amounts of energy on a regular basis, including construction workers, athletes, laborers, and others with physical occupations, should consider taking extra niacin.

Dietary Sources

The body gets niacin from food sources in two ways. One is by ingesting preformed niacin; some plants contain pure niacin and nicotinic acid amide, while meats have some preformed NAD and NADP. Also, your body makes niacin from a natural amino acid known as tryptophan, also found in many foods, but you must take in 60 mg of tryptophan to make the equivalent of 1 mg of nicotinic acid. In addition, the chemical reactions involved in converting tryptophan to nicotinic acid require pyridoxine (Vitamin B6). Thus, low B6 intake can lead to reduced niacin activity, due to the reduced conversion of tryptophan to niacin.

Most people get about half their daily niacin requirement as the pure vitamin and make the rest from tryptophan. Fortunately, both niacin and tryptophan are found in a wide variety of foods, and this makes it relatively easy to satisfy your niacin requirement by dietary means. Some rich sources of this vitamin are liver, turkey, tuna, and peanuts. Niacin is also present in coffee and beer, but you would have to drink a quart of coffee or twenty-five to thirty bottles of beer a day to reach the RDA!

Niacin is very stable when heated or stored over long periods of time. However, this vitamin dissolves easily in water and will be lost if the cooking water is discarded.

Deficiencies

Niacin deficiency has been seen in areas of the world where the basic dietary staple is corn or other unfortified cereals that are poor sources of both tryptophan and niacin. Other conditions that can contribute to niacin deficiency are gastrointestinal problems that interfere with the body’s ability to absorb the vitamin, unusual dietary habits, infections, or an overactive thyroid. Since niacin needs are related to energy production, it is easy to understand how any condition that places extra stress on the body or demands energy expenditure will increase the need for niacin.

Niacin deficiency may develop in people with a rare disease called carcinoid syndrome, even though there is no problem with vitamin intake. In carcinoid syndrome, tumors develop that make large amounts of chemicals called 5-hydroxytryptophan and 5-hydroxytryptamine. The tumors use dietary tryptophan to make these chemicals, leaving little to be converted to niacin. Niacin deficiency can also develop in people with another rare condition called Hartnup’s disease, a natural inability to absorb tryptophan from the gut.

Deficiency Symptoms

Symptoms of the classic niacin deficiency state, called pellagra, can be summarized by the “three D’s”: dermatitis, diarrhea, and dementia. Dermatitis (skin rash) is the most distinguishing feature of pellagra. The rash appears as scaling, flaking skin. Cracking and bleeding occur in more severe cases. It is usually located in areas where skin is stressed, such as the elbows, feet, hands, and areas of skin exposed to the sun, and these areas become noticeably darker than other areas of skin. Casal’s necklace, one of the best-known signs of niacin deficiency, consists of darkening of the skin on the face, neck, and back; it appears as if the victim were wearing a dark necklace.

The diarrhea of pellagra can be quite severe and will only make the problem worse. It can cause loss of appetite, reducing still further the absorption of niacin from food. This diarrhea is probably caused by lesions in the stomach and intestinal tract due to the niacin deficiency. Other gastrointestinal tract symptoms are: upset and irritated stomach, a red and swollen tongue with ores on it, and enlarged salivary glands that produce excess saliva. Nausea and vomiting are common, and about half of the people who develop pellagra also lose their digestive juices until the disorder is corrected.

Dementia, the third D, is an unusual feature of vitamin deficiency and may be simply defined as a serious mental impairment with disorientation. If left untreated, the dementia progress to the point where the victim enters a catatonic and will die in a coma. Other symptoms of niacin deficiency involving the brain and central nervous system are irritability, memory loss, anxiety, hallucinations, and delirium.

Not everyone who is niacin-deficient will develop pellagra. The most common symptoms of marginal niacin deficiency, also known as subclinical pellagra, are diarrhea, headaches, nervousness, and a swollen and red tongue.

The easiest way to test for a niacin deficiency is to measure the level in your urine of methylnicotinamide, the final product of the body’s metabolism of niacin. Low levels of this substance indicate a possible vitamin deficiency, but the test result is not always conclusive.

People Who May Benefit From supplementation

Alcoholics, pregnant and breast-feeding women, people with infections or an overactive thyroid, smokers, and those under a t deal of daily physical stress may become niacin-deficient and should consider a routine supplement.

Women taking oral contraceptives require more than the usual 60 mg of tryptophan to make the equivalent of 1 mg of niacin because their conversion rate is reduced. They should increase intake of foods high in niacin or take a nutritional supplement.

Toxicity

Doses of niacin of up to 100 mg per day usually cause no problems. However, patients taking more than 500 mg per day of nicotinic acid will experience significant adverse reactions to that therapy. Interestingly, it is nicotinic acid, not other forms of that causes the problems. However, as discussed later, only nicotinic acid has cholesterol-lowering abilities, so this is the form of the vitamin usually used in high doses. Virtually everyone taking high doses of nicotinic acid becomes flushed within two hours of taking the vitamin. The flush is usually confined to the face and hands and can be described as redness and a feeling of burning and stinging. Tolerance to this reaction develops in time, so that it often becomes less severe as time goes on. In addition, many people experience stomach upset, cramps, nausea, vomiting, and diarrhea. Liver damage can also be caused by nicotinic acid if it is taken consistently for an extended time; this is probably the most worrisome side effect associated with this vitamin. The damage is usually reversible but nevertheless worrisome. Other severe side effects of nicotinic overdose are difficulty metabolizing blood sugar (glucose), disturbed heart rhythms, a rash over large areas of the skin, and gouty arthritis. Some say the water-soluble vitamins are all nontoxic, but this is not true for nicotinic acid (and vitamin B6) in high doses.

The adverse effects of nicotinamide are less severe, and it does not cause the flushing reaction. On the other hand, it does not lower cholesterol as effectively as nicotinic acid.

INTERACTIONS

Nicotinic acid interacts with clonidine, used to treat hyper-tension, and with certain blood and urine tests.

Therapeutic Uses

Niacin supplements are given to counteract any of the deficiency symptoms reviewed earlier in this profile. However, symptoms will not be alleviated by niacin use unless they are, in fact, caused by vitamin deficiency.

In addition to the prevention and cure of pellagra, it has be known for a long time that nicotinic acid, but not nicotinamide, when given in high doses, is capable of reducing both total cholesterol and an especially bad form of cholesterol called LDL cholesterol. It will also reduce levels of triglycerides, which are undesirable blood fats, and raise levels of HDL (”good”) cholesterol, which is associated with a lower risk of heart attack and other circulatory problems. Nicotinic acid is now one of the recommended first-line agents for treating patients whose blood levels of cholesterol or triglycerides are too high. Importantly, nicotinic acid has been shown to reduce heart attacks and in the long run to reduce overall mortality in patients with previous heart disease. In combination with other lipid-lowering drugs, it has even reduced atherosclerotic lesions or plaques in blood vessels. And it is cheap, costing less than $5 per month for treatment.

What is the downside to nicotinic acid treatment for blood lipids? In brief, 1 to 5 g doses of nicotinic acid are required per day to achieve good lipid-lowering effects, and these high doses are associated with significant adverse effects. Keep in mind that the RDA value for niacin is 18 mg, so nicotinic acid treatment is using doses up to fifty times dietary levels.

Clearly this is a case of using this vitamin for its drug effects. Almost everyone taking more than 500 mg a day of nicotinic acid will experience flushing and some degree of stomach upset. Taking an aspirin one hour before the nicotinic acid dose will help reduce the flushing. Patients generally develop a tolerance to nicotinic acid, so the flushing gets less annoying with time.

Other common side effects of nicotinic acid are headache, heart burn, diarrhea, and a warty skin rash. Liver toxicity, which has been observed in some patients on nicotinic acid, is of greater concern. This effect is reversible when treatment is stopped. Nicotinic acid can activate duodenal ulcers, upset glucose balance in diabetics, and make gout worse.

Manufacturers have attempted to reduce some of the gastric complaints by formulating nicotinic acid in slow-release forms. Unfortunately, while the special slow-release dose produced less flushing than conventional nicotinic acid, more liver toxicity was detected in one study.

Between 30 and 50 percent of people taking nicotinic acid have to give up the therapy because of adverse effects. One study has shown that individualizing the dose for each patient to the lowest effective level both reduced lipids and shrank the number of patients who had to drop nicotinic acid treatment.

Our recommendation is this: Nicotinic acid is an inexpensive and valuable drug for treating patients with high blood lipids, but it is not a vitamin that should be taken in high doses without the advice and care of a qualified health care professional. Don’t self-medicate with high doses of nicotinic acid because of the chance of liver damage and other significant problems.

Unsubstantiated Claims

Treating Mental Illness

High doses of nicotinic acid have been prescribed for mental illnesses, most notably schizophrenia, for which it was first used in the early 1950s. The theory behind this use came from the fact that niacin alleviated symptoms of mental illness caused by acid deficiency. Some psychiatrists still prescribe up to 20 g a day, and hardly a month passes without the publication of another article extolling the virtues of nicotinic acid and other miracle nutrients in the treatment of mental illness.

Nicotinic acid was tested and found ineffective in the treat-F schizophrenia. The most comprehensive of these, evaluation was conducted in 1971 by the Canadian Mental Health Association. Their studies were set up as a controlled multicenter evaluation, similar to that described for the evaluation of nicotinic acid for heart disease. The findings of these careful studies are best summarized by saying that the claims of nicotinic acid enthusiasts have not been confirmed. In a comparison of such factors as the length of hospitalization and the quantity of tranquilizers consumed, the niacin group even fared worse than the placebo group. There have been other, more recent controlled studies, but the results are not consistent and generally do not support the efficacy of nicotinic acid, or any other vitamin for that matter, as a treatment for mental illness.

In this context, we would also like to add a comment concerning the placebo effect. Nicotinic acid causes flushing oft the face and a tingling sensation, which gives the impression that the drug is having profound effects on the body. A compassionate and enthusiastic therapist may use these symptoms to make patients think the drug is having an effect. It is attractive to many people to think that they can take psychiatric treatment into their own hands, avoiding traditional therapies. But we believe that using nicotinic acid without other medicines and/or psycho-therapy can be dangerous.

Other Uses

We cannot recommend that you take this vitamin to treat bad breath, canker sores, deafness, dizziness, depression, hyper-tension, skin blemishes, or tiredness. Nicotinic acid also will not prevent migraine headaches or senility, nor will it improve digestion.

Availability
Nicotinic acid (niacin) is available in tablets of 25 mg, 50 mg, 100 mg, and 500 mg. timed-release capsules and tablets in similar strengths and an elixir with 50 mg in every teaspoonful are also available. These high doses are used to lower blood fat levels, as discussed above. Niconinamide is available in capsules and tablets containing 50 mg, 100 mg, and 500 mg. niacin injections are restricted to prescription-only use.

USANA Vitamins and Nutrition - Pharmaceutical Grade Nutritional Products

Vitamin B2 (Riboflavin)

Riboflavin has a bad taste and is yellow in color. In fact, the distinct taste of multivitamin products is caused by riboflavin. Like most B-complex vitamins, riboflavin is involved with energy production. But unlike the others, a lack of riboflavin shows itself primarily as skin sores and blemishes that affect the skin surface and the lining of the stomach.

Function

Riboflavin is converted in the body into two active forms, flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD). FMN and FAD are essential to cell function because they are coenzymes (catalysts) for chemical reactions that involve utilization of oxygen and liberation of energy. This energy is used to convert food into more energy, which cells then use to perform their designated body functions. Riboflavin is found in every body cell.

Daily Requirements

As is the case with thiamin, your daily riboflavin requirement is related to the number of calories you take in each day. More calories means more riboflavin will be needed to convert food to useful energy. You should be getting 0.6 mg of riboflavin for every 1,000 calories you eat. Thus, if you are on a 3,000-calorie diet, you will need 1.8 mg a day. If you eat 2,000 calories, you will need only 1.2 mg a day, and son on.

People who expend large amounts of energy every day, including athletes, construction workers, and others with heavy physical demands, should take care to supplement their daily riboflavin intake.

Dietary Sources

Protein-riboflavin combinations are called flavoproteins and are important to all life forms. It is therefore logical that riboflavin is found in a wide variety of foods. Milk, cheese, chicken, lean beef, and pork are particularly rich sources. It has been estimated that about half of our riboflavin intake comes from dairy products. Riboflavin is stable when heated, and because it is bound to food proteins and other molecules, much of the vitamin content of foods cooked in water (about 80 percent) is retained in the finished product, even if the cooking water is discarded. Riboflavin is destroyed when mixed with chemically basic substances, like baking soda. It is also broken down by sunlight; therefore, you should keep riboflavin-rich substances away from direct sunlight. Normal room lights are not strong enough to cause much riboflavin destruction, although common sense would dictate that dark or opaque containers be used for cooking and storage in order to minimize vitamin losses.

Grains carry most of their riboflavin in the germ and bran coat. Bleaching and other refining processes used to produce white flour remove most of this vitamin from this important dietary staple. In enriched flour, riboflavin as well as thiamin, niacin, and now folic acid have been added to replace the amounts removed in processing. Enriched flour is better than nonenriched, but it makes sense to eat more unadulterated, vitamin-complete, whole-grain flour when possible.

Deficiencies

Riboflavin deficiency may be difficult to recognize because it rarely occurs alone. It is normally accompanied by other vitamin deficiencies and is most commonly found among people whose diets are inadequate or consist mostly of carbohydrates.

A person who eats too little protein will force the body to break down its own proteins, including the riboflavin-containing flavoproteins. Thus, a diet very low in protein will lead to a riboflavin deficiency unless unusually large amounts of the vitamin are obtained form dietary or other sources, and unlikely prospect if protein intake is so low.

Considering the importance of riboflavin-dependent en¬zymes to energy production and body metabolic processes, it is remarkable that riboflavin deficiencies are not more serious and life-threatening. The reasons for this are not well understood but may be due to the widespread availability of riboflavin from foods; it would be very difficult to consume a riboflavin-free diet.

Deficiency Symptom

Many of the symptoms that accompany riboflavin deficiency can be traced to a loss of the general ability to perform normal tissue repairs. The first deficiency symptoms are a general loss of facial color, sores at the corners of the mouth, and a sore throat. These may be followed by a magenta coloration of the tongue (called glossitis), red and raw lips, and skin sores (espe¬cially in cracks and around joints). A greasy, scaling rash may develop by the nose and can spread to involve both cheeks and the skin around the ears. Rashes in the genital area are common. People with severe riboflavin deficiency may become anemic or; develop nerve disease, but these are relatively infrequent.

One interesting symptom of riboflavin deficiency is the invasion of blood vessels into the cornea of the eye. This produces an appearance that can be compared to red eye or conjunctivitis. The eye, in contrast to other organs, does not contain FMN or FAD. Rather, it contains free riboflavin. It is thought that free riboflavin in the eye may play a role in bringing oxygen to tissue that have no other obvious sources of oxygen. When there is n enough riboflavin in the eye, the body compensates by growing blood vessels into the normally clear cornea to supply oxygen.

Riboflavin levels in me body are best tested by measuring the amount of vitamin passed out in the urine over a twenty-four-hour period. People who lose less than 0.05 mg per twenty-foil hours are probably deficient People with riboflavin anemias will also begin to make new red blood cells and will experience an increase in blood hemoglobin level after taking the vitamin. This effect can be monitored by routine blood counts and hemoglobin levels. In addition, people who are riboflavin-deficient may have low levels of activity of an enzyme in red blood cells called glutathione reductase.

People Who May Benefit From supplementation

Severe riboflavin deficiencies are rare in the United-States, but marginal deficiencies involving many of the symptoms described above have been observed in alcoholics. Also, dietary surveys have revealed marginal deficiencies in some senior citizens - the poor, some urban teenagers who do not drink milk regularly, and smokers.

Pregnant and breast-feeding women need extra riboflavin to meet their increased energy requirements.

Scientists have noted that women taking oral contraceptives or thyroid hormone may be riboflavin-deficient. Also, animal indicate that those who take phenothiazine (antipsychotic) drugs such as chlorpromazine (Thorazine and others) or tricyclic antidepressants such as amitryptiline (Elavil and others) may have less riboflavin in their bodies than people not taking those medicines. The reasons for this are not known.

Toxicity

Riboflavin is not considered toxic. Excess riboflavin is rapidly passed out of the body via the urine. Those who favor taking large doses of the B vitamins need only look at the bright yellow of color of their urine, caused by riboflavin, to appreciate how much of their megadose they are flushing down the toilet.

Therapeutic Uses

Riboflavin supplements may be given to counteract any of the symptoms of riboflavin deficiency reviewed earlier in this profile. However, such symptoms will not be alleviated by riboflavin unless they are, in fact, caused by vitamin deficiency.

Riboflavin has no important therapeutic use other than relief or prevention of the deficiency state.

UNSUBSTANTIATED CLAIMS

Cure for Skin and Eye Diseases

Using riboflavin to cure “red eye” caused by vitamin deficiency has led to the use of riboflavin in doses of 5 to 10 mg per day to prevent or even cure various eye diseases. Riboflavin has also been used to treat skin disorders that mimic those seen in peo¬ple with riboflavin deficiencies. These uses for riboflavin were popular earlier but have fallen into disfavor more recently. Un¬fortunately, riboflavin works in skin and eye diseases only when the reason for the disorder is the lack of riboflavin.

Other Uses

Vitamin B2 will not prevent cancer or stress, or improve repro¬ductive ability. It will not increase growth unless one is severely deficient in this vitamin.

AVAILABILITY

Riboflavin is available form various manufacturers as tablets in strengths of 25 mg, 50 mg, and 100 mg. it is an ingredient in most multivitamin products.

USANA Vitamins and Nutrition - Pharmaceutical Grade Nutritional Products